Rework as esp-idf component

CMakeLists.txt

@@ -2,6 +2,8 @@
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
 
+if(NOT DEFINED IDF_TARGET)
+
 cmake_minimum_required( VERSION 3.5...3.20 )
 project( boost_optional VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX )
 
@@ -23,3 +25,24 @@ target_link_libraries( boost_optional
         Boost::type_traits
         Boost::utility
 )
+
+else()
+
+idf_component_register(
+    INCLUDE_DIRS
+        include
+    REQUIRES
+        boost_assert
+        boost_config
+        boost_core
+        boost_detail
+        boost_move
+        boost_predef
+        boost_static_assert
+        boost_throw_exception
+        boost_type_traits
+        boost_utility
+)
+
+endif()
+